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Railway Aerodynamics for Passing and Interactions with Dynamic Effects

Objective



Objectives and content: High-speed train operation creates many problems for railways companies, due to transient aerodynamic effects. Many of these transient effects are currently
investigated in the frame of the Brite-Euram TRANSAERO project: problems of lateral wind gusts and of pressure
waves in tunnels, as well as pressures applied to passing
trains where the project deals mainly with the unsteady
aerodynamic effects associated with the passing of the nose of high speed trains.
A second category of problems is due to unsteady
aerodynamics and can be described as follows:
Unsteady pressure field due to the slipstreams and the
tail wake of the passing train which sometime generate
unsteady forces and moments of higher amplitudes than
those due to the nose passing.
Dynamic excitation coupled with the aerodynamic forces
generated by the train.
Three main problems are identified at the moment, all
with precise references from European or Japanese
sources, that evidence the reality of the technical and
economic stakes:
The safety of persons standing in the neighbourhood of
the track, when placed under the effect of aerodynamic
loads of passing trains.
The coupling of aerodynamic unsteady excitation and of
train dynamics has been observed on high-speed trains
with light front- and end-cars. It results in lowfrequency lateral oscillations that are extremely
uncomfortable for passengers. Present very-high speed
European trains have not been susceptible to these
problems until now, because end-cars are heavy power cars
without any passengers. In some countries, the trend is
now to develop high-speed trains with a distribution of
power all along the trains, and lighter end cars with
passengers. So, this problem must be addressed urgently.
The fatigue of the structures of trains under the
repeated effect of aerodynamic loads of passing trains is
not sufficiently understood to make sure that is possible
to increase the performance of high-speed passenger
trains and freight trains without facing severe
structural problems after several years of operation.
This lack of understanding and of subsequent assessed
design quantitative guidelines is considered as an
obstacle to the upgrade of performance of railway
transport.
In face of these problems, RAPIDE proposes to perform
generic research on the dynamic interaction between
aerodynamic excitation and train mechanical behaviour by
means of experimental investigations at reduced scale and
numerical modelling of the coupled system, followed by a
verification of the trends and models by means of full
scale tests. A parametric study of the phenomena will
allow guidelines for optimisation and for train design
and operation to be defined. As a conclusion of RAPIDE,
a basis for industrial development of appropriate
solutions and the development of quantitative
interoperability guidelines will be proposed.
This research is very innovative: coupling of aerodynamic
and mechanical behaviour of structures has not yet been
undertaken in such an ambitious way for railway
applications, at least in Europe (similar work has been
only reported in Japanese literature). It will rely on
the most powerful testing and simulation techniques
presently available, coming also from other transport
sectors (aeronautics and automotive). At the same time,
it addresses very practical and short-term problems with
industrial applications, as well as harmonisation rules
that should be derived from the results of RAPIDE.
Besides its positive consequences on harmonisation and
interoperability of high-speed railway traffic, RAPIDE
will also allow the exploitation in better conditions of
new technologies of high-speed trains and the development
of more flexible concepts for high-speed operation (e.g. mixed traffic), which will be a contribution to both the
sustainable development of high-speed rail traffic in
Europe, and to the competitiveness of European railway
manufacturing industry.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Deutsche Bahn AG
Address
5,Völckerstrasse
80939 München
Germany

Participants (7)

ABB Daimler Benz transportation GmbH
Germany
Address
43/1,Saatwinkler Damm
13601 Berlin
AEA Technology Plc.
United Kingdom
Address
London Road
DE24 8YB Derby
Europe Research Management SA
France
Address
22,Rue G. Eiffel
78306 Poissy
Ferrovie dello Stato SpA
Italy
Address
Piazza Della Croce Rossa 1
00161 Roma
Société Nationale des Chemins de Fer Français
France
Address
45,Rue De Londres
75379 Paris
Swiss Aircraft & Systems Company
Switzerland
Address

6032 Emmen
The Motor Industry Research Association Limited
United Kingdom
Address
Watling Street
CV10 0TU Nuneaton - Warwickshire